Electronic Letters to:

Hip: A. Rasch, A. H. Byström, N. Dalén, N. Martinez-Carranza, and H. E. Berg Persisting muscle atrophy two years after replacement of the hip J Bone Joint Surg Br 2009; 91-B: 583-588 [Abstract] [Full text] [PDF]

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Persisting muscle atrophy two years after replacement of the hip

Myron M. LaBan, Rajesh Iyer, M.D., Martin S. Tamler, M.D.   (19 June 2009)

Clinical implications of persisting muscle atrophy two years after replacement of the hip

Sunil Apsingi, Amit Sharma, Sanjiv B Manjure   (20 May 2009)

Persisting muscle atrophy two years after replacement of the hip 19 June 2009
Myron M. LaBan, Physician William Beaumont Hospital, Royal Oak, Michigan USA, Rajesh Iyer, M.D., Martin S. Tamler, M.D. Send letter to journal: Re: Persisting muscle atrophy two years after replacement of the hip myjoy{at}comcast.net Myron M. LaBan, et al.	Sir, We read this excellent article with interest and wish to add the following comments: 1. In agreement with the authors, we have previously reported pre-operative atrophy of the iliopsoas as recognised on MRI. By appropriate muscle testing, this loss of muscle bulk can be anticipated clinically by recognising the presence of weakness of the ipsilateral iliopsoas as an early sign of degenerative hip disease.1 2. Post-operative rehabilitation of the periarticular muscles of the hip “may not reflect the same qualities” in each case. In this regard, post-operative strengthening as well as increasing the bulk of these muscles may be more complex than might otherwise initially appear. Notably, the iliopsoas is a two-joint muscle acting proximally on the axial spine and distally on the femur, functionally having the capacity of reversing its osseous attachment both at its origin and its insertion as it under load cycles from a concentric/shortening to an eccentric/elongating contraction. Systemic osteoarthritis of the spine limiting flexibility and/or persistent post-operative restriction of hip joint range of motion singularly and/or together may impair the muscle’s ability ultimately to recover strength and regain normal bulk.2 3. Blix curve, a tension/length graph, is a pictorial representation of how either increasing and/or decreasing a muscle’s resting length also reduces its ability to increase tension and muscle power, especially at each end of this spectrum. Failing to approximate the normal resting length of the muscle operatively by not replicating the exact length of the fulcrum arm through which functionally the muscle acts reduces its ability to develop both power and bulk.3 M.M. LaBan, MD, MMSc, R. Iyer, MD, M.S. Tamler, MD, Department of Physical Medicine and Rehabilitation, William Beaumont Hospital, Royal Oak, Michigan, USA. 1. Laban MM. Atrophy and clinical weakness of the iliopsoas muscle: a manifestation of hip osteoarthritis. Am J Phys Med Rehabil 2006;85:629. 2. Laban MM, Iyer R, Tamler MS. Occult periarthrosis of the shoulder: a possible progenitor of tennis elbow. Am J Phys Med Rehabil 2005;84:895-8. 3. Ralston HJ, Inman VT, Strait LA, Shaffrath MD. Mechanics of human isolated voluntary muscle. Am J Physiol 1947;151:612-20.
Clinical implications of persisting muscle atrophy two years after replacement of the hip 20 May 2009
Sunil Apsingi, Clincial Fellow Luton & Dunstable NHS Trust, Luton, UK, Amit Sharma, Sanjiv B Manjure Send letter to journal: Re: Clinical implications of persisting muscle atrophy two years after replacement of the hip apsingi{at}gmail.com Sunil Apsingi, et al.	Sir, We read this paper with great interest and congratulate the authors. We would like them to clarify certain aspects of their study: 1. Was the required sample size calculated before starting the study? 2. What was the physiotherapy protocol after hip replacement? 3. Was it aimed at strengthening any particular muscle group? 4. Did the age of the patient make any difference to the muscle recovery? 5. Most importantly, what is the clinical implication of their study? Did it change their clinical practice? S. Apsingi, Clinical Fellow, A. Sharma, Clinical Fellow, S.B. Manjure Consultant, Orthopaedics, Luton & Dunstable NHS Trust, Luton, UK.