Total hip resurfacing arthroplasty may allow patients to have comparable function when compared to standard total hip arthroplasty [5–8]. The current levels of patient satisfaction and the timely return to full functional capabilities will potentially be improved with rehabilitation protocols that further develop the coordination between orthopaedic surgeons and other health professionals, as well as with the refinement of surgical techniques, pain management protocols, and appropriate patient expectations.
The limitations of this study include the short-term follow-up mean of 52 months and the still small numbers of patients (n = 147) that make this type of analysis difficult. In addition, following their initial in-patient rehabilitation program, not all patients received physical therapy at the same institution. However, all patients reported similar conventional rehabilitation protocols to make this less of a factor subject to bias.
Efforts have been made to develop standards regarding patient rehabilitation after conventional total hip arthroplasty. Youm et al  distributed a questionnaire to the 650 active members of the American Association of Hip and Knee Surgeons to evaluate surgeons' recommendations concerning postoperative rehabilitation and activity restriction. The authors used mean response scores to indicate a recommended standardized postoperative management protocol. Some of these recommendations included the use of an abduction pillow, a high toilet seat, a high chair for 6 weeks, as well as restricted hip flexion for 8 weeks. They also indicated that activities of daily living should be restricted until 5 weeks for driving, 6 weeks for sitting in an office chair, 7 weeks for carrying a brief case, 11 weeks for bending the hips and working on the hands and knees, and 12 weeks for climbing a ladder. Recommended activity levels were dependent on cemented or cementless stems. Nearly all respondents limited weight carrying to 10 pounds at 7 weeks for cemented stems and 8 weeks for cementless stems. While standardized rehabilitation techniques provide excellent results in most patients, the results of the present study suggest that there are some patients who may require additional customized protocols, especially younger patients. In addition, certain patients may need less rehabilitation.
In addition to establishing standards for the participation in functional activities and rehabilitation protocols, the use of a comprehensive, multidisciplinary, inpatient rehabilitation regimen has been shown by Dohnke et al  to be important in providing optimal outcomes after total hip arthroplasty. Their study evaluated the clinical outcome of 1,065 total hip arthroplasty patients for whom a coordinated multidisciplinary approach was followed. The inpatient rehabilitation began approximately 3 weeks (mean 22 days) after surgery, and the mean length of stay was approximately 23 days. Significant improvements in disability, pain, depressive symptoms, and ability to function independently were made postoperatively from the time of admission to discharge from the inpatient rehabilitation program.
While the present study suggests that current rehabilitation protocols for hip resurfacing patients yield satisfactory results, it remains unclear whether these programs are optimal. The protocols were originally designed for total hip arthroplasty patients who often are older and less active than many resurfacing patients. In the present study, there were three patients who discontinued rehabilitation after reaching all functional goals by 6 weeks post-operatively. Based on their excellent results and accelerated progress, they were cleared by their physical therapist (AB) and surgeon (MAM) from any additional prescribed rehabilitation. These results were similar to those reported by Crow et al. who found that a multimodal treatment approach allowed a 43 year-old man to return to sports activity following bilateral resurfacing . Their rehabilitation approach focused on joint mobilization and the patient achieved approximately 90 degrees of hip flexion and 10 degrees of lateral rotation bilaterally by 3 months postoperatively. In another study, Newman et al. also suggested that new rehabilitation standards may need to be adapted for resurfacing patients . They assessed the outcomes of 126 hip resurfacing patients and reported excellent return to function following resurfacing with a mean Oxford Hip Score of 15 points and UCLA Activity Score of 7 points. However, they reported that approximately 1 out of 4 of the patients reported persistent pain with decreased strength and a reduced hip flexion at a mean of 95 degrees (+/- 13 degrees). They concluded that the suboptimal recovery for some of their cohort may have been attributed to the rehabilitation protocols that were originally developed for standard total hip arthroplasty patients and not for their resurfacing arthroplasty counterparts.
Based partly on the results of this study, we currently we allow considerable variation from the previously described protocol for patients who are treated with a hip resurfacing arthroplasty, with progression based on the ability to achieve certain functional goals, rather than using only time since the index arthroplasty, which has most often been used in the past. Thus, some patients can be treated in an individual manner based on their ability to achieve certain functional milestones. Our current rehabilitation goal by five weeks following surgery is for the patient be able to ambulate pain free using single point cane in the opposite hand, go up and down the a flight of stairs, flex their hip to 90 degrees, and abduct to 30 degrees. We avoid strengthening exercises of the hip that are associated with pain, and specifically avoid side lying hip abduction strengthening early because of our anterolateral surgical approach. If patients achieve these well-defined goals earlier than 5 weeks we recommend faster progression to full range of motion, including rotation. We also progress patients to weight bearing as tolerated without the use of an assistive device, and place patients on progressive resistive exercises to improve hip abductor and extensor strength as long as resistive exercise does not cause pain. Accelerated, rather than time based, rehabilitation performed in this fashion may reduce the total time spent in rehabilitation for a number of patients. This preliminary study suggests that in general, a major commitment to rehabilitation should be made by patients to achieve the best clinical outcomes. In addition, patients who remain stiff or have difficulty progressing may require additional, tailored rehabilitation regimens. Conversely, patients who rapidly regain excellent function and a high activity level following surgery may be able to avoid further rehabilitation once certain goals are met. However, further investigation and multi-center studies need to be performed to confirm and refine these conclusions.
Based on the results of the current study, we suggest that increased body mass index may have a negative correlation with patient commitment to rehabilitation. Similar results were reported by Vincent et al. who examined whether obesity affected inpatient rehabilitation outcomes after total hip arthroplasty . In their study, all patients completed an interdisciplinary inpatient rehabilitation program after surgery and were evaluated using functional independence measure scores, length of stay, efficiency scores (functional independence measure scores/length of stay), hospital charges, and discharge disposition location. Although functional independence measure scores improved from admission (mean of 25 points) to discharge (mean of 29.5 points) in all groups, the efficiency scores, length of stay functional independence measure scores, length of stay, and total charges were curvilinearly related to body mass index. They concluded that while elevated body mass index does not prevent functional gains in total hip arthroplasty patients during inpatient rehabilitation, increasing body mass index does influence efficiency, length of stay, and hospital charges in a negative manner. Furthermore, severely obese patients can achieve physical improvements, but at a lower efficiency and greater cost.
The use of a comprehensive activity and rehabilitation tool such as the one reported in the present study may allow surgeons to predict the postoperative recovery course for patients for hip resurfacing as well as other arthroplasty treatments, and allow for a tailoring of rehabilitation treatments. Additionally, it may assist surgeons in providing guidance regarding which treatment modality may be most appropriate for a given patient. Further study is necessary to better define these potential benefits.